After 12 months and $250,000, an inquiry into leaked Foreign Affairs Cabinet papers may never see the light of day.

In the High Court at Wellington yesterday, the lawyer for a person known only as "A" said the report by inquiry head Paula Rebstock voiced a "strong suspicion" that his client was responsible for the unauthorised disclosure of sensitive Cabinet documents, but offered no evidence to back it up.

The legal challenge has been shrouded in secrecy and Justice Robert Dobson yesterday suppressed all details leading to the identify of "A", including gender, present occupation and identity of the organisation involved.

"A" is challenging Ms Rebstock's right to issue a final report.

Lawyer Jason McHerron told the court it was clear Ms Rebstock intended to proceed to find that "A" was responsible for the unauthorised disclosure of two Cabinet committee papers at the centre of the leak inquiry.

That was despite "A" denying being responsible.

Last month, Justice Dobson agreed to an injunction to delay the completion of Ms Rebstock's report pending a judicial review. He also issued a gagging order against Ms Rebstock and State Services Commissioner Iain Rennie, who ordered the inquiry.

Ms Rebstock's inquiry was ordered after Labour foreign affairs spokesman Phil Goff claimed under parliamentary privilege to have leaked details of plans for restructuring at the Ministry of Foreign Affairs and Trade.

The details came from sensitive Cabinet committee documents.

The court heard yesterday "A" scanned and copied Cabinet documents but had repeatedly denied distributing them. A forensic examination was unable to find any evidence "A" sent the documents to anyone else. Without such evidence, the allegation should not be repeated, Mr McHerron said.

Crown lawyer Una Jagose said there was enough evidence to warrant suspicion.

The answers given by "A" during two interviews were not unequivocal and left some doubt in Ms Rebstock's mind.

It was for Mr Rennie to decide whether to publish the report, but Ms Rebstock should not be prevented from giving it to Mr Rennie, Ms Jagose said.